Apparently Core i7 920 takes the crown in terms of average overall performance. However since the benchmark suits contains some encoding and CPU-intensive benchmarks, it may not apply to you if you're just looking for a gaming CPU. For gaming, Phenom II X4s are a much better values.
I actually think the Phenom II's are a better price/performance value at stock.. However, if you OC your i7 I believe it's value increases dramatically.